Unconscious patients’ brains react

Scans offer promise of measuring who is truly in vegetative state

Numbers

An estimated 9,000 to 37,000 people in the United States are in a persistently vegetative or minimally conscious state; the number ranges widely because diagnostic definitions are vague.

In a study certain to rekindle debate over life-sustaining care for those with grievous brain injuries, researchers report that five patients thought to be in a persistent vegetative state showed brain activity indicating awareness, intent and, in one case at least, a wish to communicate.

Of 54 unresponsive patients whose brains were scanned at medical centers in England and Belgium, those five appeared able, when prompted by researchers, to imagine themselves playing tennis, and four of them demonstrated the ability to imagine themselves walking through the rooms of their homes.

One of those patients – a 22-year-old man who had been unresponsive for five years following an automobile crash – went on to respond to a series of simple questions with brain activity that clearly indicated yes or no answers, according to the researchers.

Their work is the first to give physicians and families the prospect of a biological test to determine whether a patient who shows no response to his or her surroundings is conscious and aware of them.

That information, in turn, could bring comfort to families and better care to patients who are able to demonstrate their awareness and communicate their needs. For those consistently unable to respond, such tests may bring a measure of comfort to families inclined to withdraw life support. The research was published online Wednesday in the New England Journal of Medicine.

But some neurologists cautioned that such a new diagnostic technique might further confound families.

In an accompanying editorial, Harvard University neurologist Allan H. Ropper wrote: “It will now be difficult for physicians to tell families confidently that their unresponsive loved ones are not ‘in there somewhere.’ ” Even where a patient has shown purposeful brain response, “we cannot be certain whether we are interacting with a sentient, much less competent, person.”

Regardless, the study demonstrates that certain brain scanning might be used to discern the extent of a patient’s consciousness. It is the latest in a growing body of research suggesting that methods of classifying unresponsive patients often fail to predict the possibility of recovery.

All of the subjects whose brains showed signs of awareness and intent in the study published Wednesday had suffered traumatic brain injury – most commonly sustained in falls, motor vehicle accidents, collisions and assaults. Of the 44 subjects who failed to respond, half had sustained brain trauma and half had been subject to illness or injury that deprived them of oxygen.

The study’s lead author, Martin M. Monti, said that he and his colleagues were “absolutely stunned” when, watching the shadowy images of Subject No. 23’s ostensibly vegetative brain, they detected clear responses to yes-or-no questions.

A staff neuroscientist with the British government’s Medical Research Council, Monti said the possibility of unlocking the wishes of previously mute patients “certainly contributes to the debate” over a patient’s right – and ability – to express his desire to die. But that was not among the questions asked of subject No. 23, he said.